Automatic well shut-off apparatus

ABSTRACT

An automatic well shut-off apparatus which is adapted to be disposed in a well below a single or multiple string packer for automatically shutting off the flow of fluid upwardly in a well when the pressure differential between the well fluid externally of the apparatus and the pressure in the apparatus reaches a predetermined amount. The apparatus includes a collapsible sleeve which collapses to a closed or shut-off position only when the predetermined pressure is reached and it is sufficient to overcome the collapse resistance of the sleeve.

United States Patent 1 Kirkpatrick et al. Feb. 20, 1973 s41 AUTOMATIC WELL SHUT-OFF 3,494,588 2/1970 Kisling ..251/5 APPARATUS 3,552,712 1/1971 Whitlock ..25l/5 [76] Inventors: Maurice Kirkpatrick, 4734 Briarbend; Donnell E. Waggener, 5035 jnmary g i g qf Leipmk Yarwell, both of Houston, Tex. tummy rave 1 & Matt ews [22] Filed: Feb. 10, 1971 57 ABSTRACT PP'- N04 114,228 An automatic well shut-off apparatus which is adapted to be disposed in a well below a single or multiple 52 US. Cl. ..166/224 .String packet for automatically Shutting Off the flow of 51 int. Cl. .1221]; 33/00 fluid p y in a well when he pre r differential [58] Field of Search ..l66/224; 251/5; 137/525 between the Well fluid ex ernally of the apparatus and the pressure in the apparatus reaches a predetermined [56] References Cited amount. The apparatus includes a collapsible sleeve which collapses to a closed or shut-off position only UNITED STATES PATENTS when the predetermined pressure is reached and it is 2,812,822 11/1957 OReilly ..l66/224 sufficient to overcome the collapse resistance of the 3,283,823 ll/l966 Warrington ..175/321 sleeve. 3,349,856 10/l967 Richardson ..175/321 3,396,448 8/1968 Kisling ..25l/5 7 Claims, 3 Drawing Figures l I, f i l-1 pmmgpriazolms luwJ Whom & MaHLewL ATTORNEYS AUTOMATIC WELL SHUT-OFF APPARATUS BACKGROUND OF THE INVENTION The field of this invention is well control devices for preventing well blowouts.

In recent years, particularly since the advent of offshore drilling for oil, the control of wells blowouts has become even more of a problem than in the past. Well blowouts result in well fires and in pollution of the ocean waters by the oil flowing from the well after the fire is extinguished unless the well is brought under control. Therefore, this problem of bringing wells under control has been of paramount concern.

SUMMARY OF THE INVENTION ERIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation, partly in section, of the apparatus of this invention in position for use in a well casing or pipe; I

FIG. 2 is an enlarged vertical sectional view of the apparatus of this invention in the normal open position; and

FIG. 3 is a view similar to FIG. 2, but illustrating the apparatus of this invention in the shut-off or closed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, the letter A designates generally the apparatus of this invention which is particularly adapted for use in a well pipe or casing C wherein oil or other well fluid is being produced from a well formation (not shown). Preferably, the apparatus of this invention is connected to a flow tube which is formed integrally with or is connected to a packer P which is disposed in the well pipe or casing C. Production tubing T extends upwardly to the surface above the level of the platform P or ground level where'the usual Christmastree D is provided for controlling the discharge and inlet of various fluids with respect to the casing and the tubing T. Such control includes valves such as valves 1 1 and 12 shown in FIG. 1 in the known manner. In offshore rigs, the platform P may be the deck of a floating barge or other similar installation.

This invention is illustrated with a single string of pipe T and a packer P which accommodates just the single string, but is should be understood that the apparatus A may be used with multiple strings of pipe and multiple string packers, as will be more evident hereinafter. Thepacker P may be a drillable permanent type packer or any other type of packer which is set in the casing C and which is adapted to receive the lower end of the tubing string T in sliding sealing engagement therewith. Since the packer P may have any conventional construction, it is illustrated only schematically in the drawings.

The apparatus A if this invention includes an outer housing 12 which is formed of a rigid material such as stainless steel. The housing 12 is tubular and it has internal threads 12a at its upper end for threaded engagement with threads 10a on the flow tube 10. Any other suitable means of connecting the upper end of the housing 12 to the flow tube 10 may of course be provided. The tubing string T extends downwardly into the flow tube 10, but its lower end 14 terminates above the lower end of the flow tube 10 so that the tubing string T does not extend downwardly into the housing 12. Preferably, the lower end of the tubing string T fits loosely within the flow tube 10 so that some relative movement therebetween occurs as the tubing expands and contracts under normal changes in temperature occurring during flow conditions. The seal between the tubing string T and the packer P is of course maintained even though the tubing string T moves relative to the packer P.

A collapsible sleeve 20 which is formed of rubber or a rubber like material so that it is resilient is disposed in the housing 12, preferably so that its outer external surface engages the internal surface of the housing 12 so that it is fully supported against outward extrusion or expansion during the normal flow of fluid through the bore 20a of the sleeve 20. To provide a predetermined collapse resistance for the sleeve 20 it is preferable to have a flexible metallic screen 21, usually of stainless steel, embedded within the rubber or other material forming the collapsible sleeve 20.

The external surface of the sleeve 20 is exposed to the fluid pressure in the well by reason of a plurality of slots or openings 12b which are formed in the wall of the housing 12 so as to provide a sufficient area of exposure for the external surface of the sleeve 20 to accomplish a collapse and a closing of at least a portion of such sleeve 20 when a predetermined pressure differential exists across the sleeve 20.

In the preferred embodiment of the invention, the upper end of the sleeve 20'is secured so that it does not collapse when a portion of the sleeve 20 therebelow collapses to the closed position (FIG. 3). By reason of the upper end of the collapsible sleeve 20 remaining substantially uncollapsed while the portion therebelow is in the collapsed condition, the return of the sleeve 20 from the collapsed condition of FIG. 3 to the normal open position of FIG. 2 may be more readily effected by fluid pressure from the tubing string T moving downwardly when it is desired to open the sleeve 20 again. In the preferred form of the invention, the securing of the upper end of the sleeve 20 is accomplished by bonding or vulcanizing the upper edge 20b of the sleeve 20 to the lower annular edge or shoulder 25a of a sleeve 25 which is welded or is otherwise secured in the upper end of the housing 12. The sleeve 25 is thus a retainer tube and it may be integral with the housing 12 if desired. The bore 25b of the retainer tube 25 is preferably of the same size and in alignment with the bore 20a of the collapsible sleeve 20. The sleeve 25 may be separate from the casing 12 and may be insertable along with the sleeve 20 since it is confined in its seated position as shown in FIGS. 2 and 3 by reason of the engagement of the upper edge 25c thereof with the lower end 10b of the flow tube 10.

The lower end of the housing 12 is preferably formed with an annular lip 30 which terminates in an opening 30a which is of substantially the same size as the bore 20a of the sleeve 20. One or more ports or openings 30b are provided so that fluid pressure externally of the housing 12 acts upon the lower end of the sleeve 20 to urge same upwardly to assist in an effective seal between the walls of the sleeve 20 when they are collapsed as shown in FIG. 3.

To reduce or minimize wear on the rubber or other material of the sleeve 20 as a result of the flowing fluid through the bore 20a thereof, it is preferable to provide a wear sleeve 35 on the inside lower portion of the bore 20a. Such sleeve 25 is formed of ceramic or other hard material which normally does not collapse and therefore the lower end of the sleeve 20 retains its approximate diameter even though the portion thereabove collapses as shown in FIG. 3. If such wear ring 35 is omitted, the lower portion of the sleeve 20 collapses to the same extent as the portion thereabove, except for the very upper end which remains open as previously explained because of the securing thereof to the retainer tube 25.

In the use of the apparatus A of this invention, the apparatus A is mounted on the lower end of a packer flow tube which may extend downwardly from a single string or multiple string packer in the known manner. Under normal operating conditions the oil or other well fluid flowing from the well formation would flow upwardly in the casing C and through the bore a of the sleeve 20 and then upwardly through the tubing T to the conventional equipment D at the platform P or other surface location.

In the event the well pressure increased considerably and the pressure was great enough to cause a blowout condition which might result in a blowing out of the oil in an uncontrolled manner or even a fire at the surface, the rapidly flowing oil creates a pressure drop through the inside of the sleeve 20 so that there is a pressure differential created across the wall of the sleeve 20 which is sufficient to collapse the sleeve 20 from the position shown in FIG. 2 to the position shown in FIG. 3. As soon as the sleeve 20 begins to collapse to some extent, the pressure drop internally of the sleeve 20 increases so that there is a very rapid closing of the sleeve 20 once it starts to close. Also, since the pressure from below the sleeve 20 acts upwardly thereon after the sleeve 20 has closed, it tends to compress the rubber or other resilient material forming the collapsible sleeve to obtain a more effective seal between the walls of the portion of the sleeve 20 which are engaged.

Since the upper end of the sleeve 20 remains open, fluid may be pumped downwardly through the tubing string T to reopen the sleeve 20 and return it to its normal open position when well conditions dictate such action.

As -a modification of the sleeve 20 illustrated and described above, it is possible to provide only a section or portion of the length of the sleeve 20 which actually collapses by having such section made of a more yieldable collapsible material than the rest of the sleeve 20. For example, the central portion of the sleeve 20 may be made of a softer rubber than the rest of the sleeve 20 so that collapse is initiated at the central portion of the sleeve 20 by a predetermined fluid pressure differential acting across the sleeve 20.

It will be appreciated that under normal flow conditions, the well pressure inside of the sleeve 20 will be substantially equal to the well pressure externally thereof and below the sleeve 20. However, when there is a sudden surge of well pressure as a result of a blowout condition in the well, then the size of the bore 204 serves as a sufficient restriction to flow so that a pressure drop occurs and there is a reduced pressure inside of such bore 20a as compared to the pressure externally thereof. The collapse resistance of the sleeve 20 is thus determined to cause a collapse of such sleeve 20 when the pressure differential acting on the sleeve 20 is such that a blowout of the well fluid would occur if the well fluid were not shut off. With this invention, the well fluid is automatically cut off when such blowout condition occurs, thus preventing pollution by oil spillage at the surface by reason of a blowout and also preventing a well fire.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

We claim:

1. An automatic well shut-off apparatus connected below a well packer and to a packer flow tube extending downwardly from the well packer for automatically closing off a well to prevent a blowout thereof, comprising:

a tubular housing having means at its upper end connected to a packer flow tube and having its lower end open to well pressure;

a resilient collapsible sleeve disposed in said tubular housing and having a bore therethrough which is normally open for the flow of fluid through said sleeve; and

said housing having a plurality of openings through the wall thereof and with a substantially smooth external surface surrounding and in proximity to said openings communicating fluid pressure in the well externally of said housing to the external area of said sleeve.

2. The structure set forth in claim 1, including:

a non-resilient retainer tube secured in said housing near the upper end thereof to prevent collapse of the upper end of said sleeve;

said retainer tube having a lower shoulder engageable by the upper end of said collapsible sleeve; and

means securing the upper end of said collapsible sleeve to said retainer tube to prevent its collapse so that it will be open for receiving fluid from above the sleeve to return it to its normal open condition after the pressure differential falls below said predetermined amount.

3. The apparatus set forth in claim 1, wherein:

said resilient collapsible sleeve is formed of rubber or rubber-like material having a flexible metallic screen embedded therein to provide predetermined collapse resistance.

4. The apparatus set forth in claim 1, wherein:

said sleeve has a lower annular edge which is free to move upwardly relative to said housing; and

the lower end of said housing has an outer annular lip substantially coextensive with the lower annular edge of said sleeve when said sleeve is in the normally open position for supporting same to prevent extrusion thereof during normal flow conditions.

5. An automatic well shut-off apparatus for automatically closing off a well to prevent a blowout thereof, comprising:

a tubular housing having means at its upper end for connection to a packer flow tube;

a resilient collapsible sleeve disposed in said tubular housing and having a bore therethrough which is normally open for the flow of fluid through said sleeve;

support means in said housing attached to only the upper end of said collapsible sleeve, leaving the lower end of said sleeve unattached to both said housing and said support means and free to move upwardly in said housing upon the application of well pressure to said sleeve from externally thereof; and

said housing having a plurality of openings through the wall thereof for communicating fluid pressure in the well externally of said housing to the external area of said sleeve for effecting a collapse of at least a portion of said sleeve to close off fluid flow through said sleeve when a predetermined pressure differential develops across the sleeve.

6. The apparatus set forth in claim 5, wherein:

the lower end of said housing has an annular lip substantially coextensive with the lower edge of said sleeve; and

said lip has port means for establishing fluid communication with the lower end of said sleeve for urging said sleeve upwardly to increase the effective sealing contact of the walls of the collapsed portion of the sleeve in the closed position.

7. The apparatus set forth in claim 5, including:

a wear ring secured in the inside lower end of said sleeve for minimizing wear on said sleeve during normal flow through said sleeve when it is in the open position.

III 

1. An automatic well shut-off apparatus connected below a well packer and to a packer flow tube extending downwardly from the well packer for automatically closing off a well to prevent a blowout thereof, comprising: a tubular housing having means at its upper end connected to a packer flow tube and having its lower end open to well pressure; a resilient collapsible sleeve disposed in said tubular housing and having a bore therethrough which is normally open for the flow of fluid through said sleeve; and said housing having a plurality of openings through the wall thereof and with a substantially smooth external surface surrounding and in proximity to said openings communicating fluid pressure in the well externally of said housing to the external area of said sleeve.
 1. An automatic well shut-off apparatus connected below a well packer and to a packer flow tube extending downwardly from the well packer for automatically closing off a well to prevent a blowout thereof, comprising: a tubular housing having means at its upper end connected to a packer flow tube and having its lower end open to well pressure; a resilient collapsible sleeve disposed in said tubular housing and having a bore therethrough which is normally open for the flow of fluid through said sleeve; and said housing having a plurality of openings through the wall thereof and with a substantially smooth external surface surrounding and in proximity to said openings communicating fluid pressure in the well externally of said housing to the external area of said sleeve.
 2. The structure set forth in claim 1, including: a non-resilient retainer tube secured in said housing near the upper end thereof to prevent collapse of the upper end of said sleeve; said retainer tube having a lower shoulder engageable by the upper end of said collapsible sleeve; and means securing the upper end of said collapsible sleeve to said retainer tube to prevent its collapse so that it will be open for receiving fluid from above the sleeve to return it to its normal open condition after the pressure differential falls below said predetermined amount.
 3. The apparatus set forth in claim 1, wherein: said resilient collapsible sleeve is formed of rubber or rubber-like material having a flexible metallic screen embedded therein to provide predetermined collapse resistance.
 4. The apparatus set forth in claim 1, wherein: said sleeve has a lower annular edge which is free to move upwardly relative to said housing; and the lower end of said housing has an outer annular lip substantially coextensive with the lower annular edge of said sleeve when said sleeve is in the normally open position for supporting same to prevent extrusion thereof during normal flow conditions.
 5. An automatic well shut-off apparatus for automatically closing off a well to prevent a blowout thereof, comprising: a tubular housing having means at its upper end for connection to a packer flow tube; a resilient collapsible sleeve disposed in said tubular housing and having a bore therethrough which is normally open for the flow of fluid through said sleeve; support means in said housing attached to only the upper end of said collapsible sleeve, leaving the lower end of said sleeve unattached to both said housing and said support means and free to move upwardly in said housing upon the application of well pressure to said sleeve from externally thereof; and said housing having a plurality of openings through the wall thereof for communicating fluid pressure in the well externally of said housing to the external area of said sleeve for effecting a collapse of at least a portion of said sleeve to close off fluid flow through said sleeve when a predetermined pressure differential develops across the sleeve.
 6. The apparatus set forth in claim 5, wherein: the lower end of said housing has an annular lip substantially coextensive with the lower edge of said sleeve; and said lip has port means for establishing fluid communication with the lower end of said sleeve for urging said sleeve upwardly to increase the effective sealing contact of the walls of the collapsed portion of the sleeve in the closed position. 